Acts of Volitation has a great article on Open Source and Interface Design, where basically he says that while OSS was once the great example of crappy design, there are some large projects that stand out now as clear examples of design done right.
Hopefully my quoting hasn't mangled his point too much. Just go and read the link :)
Open Source software is regularly criticized, often fairly, for lacking in ease-of-use and polish. When a developer wants a new feature - he can add it to the software, and if it gets checked-in by the project owners, it will be there for all to use.
[But, Firefox] provides a better browsing experience than it’s ancestor, Mozilla Navigator, despite having far fewer features and functions. Smart default settings and an overall better understanding of the experience of using the application by the developers helped make it better for everyone.